ES2303335T3 - ROTATING HEAD FOR GARDEN TRIMMERS, OF THE TYPE THAT INCLUDES PIVOTING CUTTERS. - Google Patents

Abstract

Rotary head (10) for garden trimmers, of the type that has its cutting means (28, 30) pivoting in the head (10), comprising a lower body part (12) and an upper annular body part (14) , the lower body part (12) can be coaxially fixed to the drive shaft (20) of the trimmer and presenting several fixed pivots (18), parallel to the axis of rotation (20) of the head (10), to pivot the cutting means ( 28, 30) provided with an eyelet, the upper body part (14) being coaxially applied in its working position to the lower body part (12), a position in which the cutting means (28, 30) are retained on the corresponding fixed pivots (18), characterized in that the fixed pivots (18) protrude upwards from the lower body part (12), and because to apply the upper body part (14) to the lower body part (12) in said working position are provided connection means d and bayonet (22, 24) that require a coaxial movement to make the two body parts (12, 14) approach each other and a rotation of the upper body part (14) around the lower body part (12 ), this rotation being opposite to the direction of rotation (R) of the head (10) when it is working.

Description

Rotary head for garden trimmer, of the type comprising pivoting cutting means.

The present invention relates to trimmer from garden and, more particularly, to garden trimmers in the that the rotary head is equipped with several cutting elements pivoting at one of its ends in angular positions equidistant from the same head, so that during the trimmer operation each of these means cutters can rotate around its pivot axis, which is parallel to the axis of rotation of the head.

In a first known head of this type, in that the cutting means have the shape of a blade or plastic blade and are equipped with an extreme eyelet for your pivot to the head, the latter has approximately the shape of a disk composed of a piece of upper body and a piece lower body joined together by a central screw that fixes also the head to the trimmer drive shaft. Said cutting means with blades are normally a total of three, which are pivoted normally by screws and nuts corresponding. Each screw acts as a pivot pivot on which the eyelet of the corresponding blade is mounted.

When a blade must be changed, for example because it is worn or damaged, you have to use a tool (usually a screwdriver) to unscrew the screw pivot corresponding to that blade. By doing this, Care must be taken not to lose the nut, screw or Washer normally placed under the screw head. As the trimmer is used on grassy or bushy grounds, if One of these pieces falls, it is not easy to find it. When has removed one of the screw pivots, the blade corresponding can be replaced by a new blade, being inserted the same screw pivot through its eyelet pivot and then through the corresponding hole arranged in the head (not forgetting the washer), screwing finally then the screw pivot in its nut (normally contained in a recess arranged in the head to prevent its rotation), after which the trimmer can return to function.

Another known head equipped with means pivot cutters comprises an upper body piece and a lower body piece joined by a central screw. For replace the blades, the two body parts have to be separated. For each blade, a corresponding fixed pivot that protrudes down is arranged on the face that is directed towards the bottom of the upper body piece to receive the pivoting eyelet of that blade. When both body parts are joined by said central screw, the blades cannot be extracted from the corresponding pivots because the corresponding parts of the lower body piece they rest on the lower end of said fixed pivots. By consequently, even to replace only one blade, the two body parts have to be separated by removing the screw central.

An additional known head of the type that Includes pivoting blades is the one described in the model Italian utility number 246620 (FR-A-2792162) by the same holder than the present patent application. This head includes also a piece of upper body and a piece of lower body, joined by screws in angularly equidistant positions, which they do not have to be removed, however, to replace the blades In this head, when it has been mounted, the pivot pivot for each blade can be moved in both senses along its axis - which is parallel to the axis of rotation of the head - between a first and a second position. When is in its first position, the pivot can be attached to the eyelet of pivoting of the corresponding blade without the possible decoupling, while with the pivot in its second position, The blade can be removed. Each pivot stays in its First position thanks to a coil spring. A pivot it simply has to be pressed against the action of said spring, for example using a screwdriver, to move the pivot from its first position to its second position in order to be able to remove the blade. The new blade can be mounted then in position to properly position your eyelet and to then release the pivot.

To replace all the blades of this head, the operation described above to replace one of them is you have to repeat a number of times equal to the number of blades, which therefore requires some time. Any way, in order to achieve this, a tool is needed (for example said screwdriver).

In addition, in this head, the pivots movable lose their ability to slip over time, until they get stuck due to the uneven wear of their seat walls

Before indicating the objectives of this invention and explain the means used to achieve them, it It should be noted that different cutting means are known than plastic blades mentioned above, all of them equipped with a pivoting eyelet and, in particular, the means cutters described in the Italian utility model application MI2005U000288 number of the same holder as this application for patent, from whose pivot eyelet one or more extend elongated flexible elements, in particular two elements parallel filiforms. As described in the document MI2005U000288, each elongated element preferably has a flattened cross section (for example elliptical) with its dimension main in the cutting plane and its largest sectional area transverse near pivot eye.

Hereinafter, the expression "media cutters "means, therefore, said blades or cutting means just described comprising one or more flexible elongated elements.

The technical problem to be solved hereby invention consists in disclosing a rotary head to a garden trimmer, of the type comprising cutting means pivoting to it, that does not present the inconveniences before indicated of the heads of this type described above. In In particular, the head is required to have a radial dimension smaller than the head described and illustrated in the utility model 246620, so that length cutting means can be used of greater cutting in a garden trimmer of cutting diameter predetermined; the head must also allow the media Cutters are mounted and replaced more quickly.

The objectives mentioned above are they get thanks to the garden trimmer head of the present invention, comprising a lower body part and a piece of upper annular body, being able to coaxially fix the lower body part to the trimmer drive shaft and presenting several fixed pivots, parallel to the axis of rotation of the head, to swing the cutting means provided with a eyelet, being able to coaxially apply the upper body piece in its working position to the lower body part, position in which the cutting means are retained on the pivots corresponding fixed, characterized in that the fixed pivots protrude upward from the lower body piece, and because to apply the upper body part to the body part lower in said working position are provided means of bayonet connection that require a coaxial movement to make that the two body parts approximate each other and a rotation of the upper body part around the body part lower, this rotation being opposite to the direction of rotation of the head when working.

In addition to allowing a replacement considerably faster than the cutting means, the solution described above allows a spindle that has diameter and weight smaller than those of utility model 246620. Conveniently, elastic means are provided to oppose the removal of the upper body part from its position of job.

Also conveniently, with the means of bayonet connection, means are associated that allow the upper body piece also assume a second position, in the that the cutting means can be replaced, also being conveniently provided elastic means to oppose the removal of the upper body part from said position of replacement of the cutting means.

The invention will be more evident from the subsequent description of one of its embodiments provided as an example. This description refers to the accompanying drawings, in which:

Figure 1 is a view, in perspective, and with the disassembled parts of a head according to the present invention;

Figure 2 is a diametral section, coaxial, to through the head when mounted, with the body part superior in his work position;

Figure 3 is similar to Figure 2, but with the upper body part in the replacement position of the cutting means;

Figure 4 is a perspective view of the head to which two different types of media have been applied cutters

As you can see from the figures, the rotary head (10) for a garden trimmer has global disk shape, of the type capable of accommodating cutting media pivoting, and comprises a lower body part (12) and a upper annular body part (14). The lower body piece (12) may be fixed in a known manner to the drive shaft of the trimmer (not shown), being indicated by (20) the axis of this tree and coinciding with the axis of rotation of the head (10). The lower body piece (12) features a centerpiece that is extends upwards (16), and four fixed pivots that extend upwards (18) arranged angularly equidistant, with the same radial distance from the axis (20) and parallel to this latest.

Four angular grooves angularly equidistant, indicated by (22) and having the typical L-shape of the grooves used in the connection means of bayonet, are arranged on the side surface of the piece central (16).

The upper body part (14) presents internally four angularly equidistant teeth (24) (only three are visible in figure 1) directed radially towards the axis (20) and forming part of said bayonet connection means, each tooth (24) being arranged to cooperate with one of the grooves (22), the latter typically presenting a part vertical and a horizontal part (26) that form the L, whose end Closed bottom receives the corresponding radial tooth (24) when the upper body part (14) is in its working position. When in this position, the upper part of the fixed pivots (18) rest against corresponding flat surfaces (52) arranged on the underside of the upper body part (14) (as shown in figure 2), so that the means cutters (for example those indicated by (28) and (30) in the figure 4), when mounted on the corresponding fixed pin (18), no can be decoupled from the latter. In this specific example, the lower body part (12) also comprises teeth (54) on which rests the upper body piece (14).

Elastic means (32), which consist of a helical spring that works both compression and torsion, keep the radial teeth (24) at the closed end of the horizontal part (26) of the corresponding grooves (22), of so that the upper body part (14) cannot be decoupled accidentally of the lower body part (12) when the garden trimmer is not working while when is working, there is no possibility of decoupling anymore that the orientation of the horizontal part (26) of the groove (22) is chosen so that when the head (10) rotates (in the direction indicated by the arrow -R- in figure 4) the teeth Radials (24) are held against the closed end of said horizontal part (26).

The helical spring (32) has a curved lower end (34) to be inserted into a notch (36) arranged on the inner edge of the upper body part (14), and a curved upper end (35) to be inserted into a corresponding hole (38) disposed in an annular element (40), whose purpose, together with a split retaining ring (42) and the discontinuous annular groove (46) disposed on the centerpiece (16), is to prevent the separation of the two body parts (12) and (14). In this regard, once the head (10) is mounted by properly rotating the annular element (40) in the direction of the arrow (M) of Figure 1, the notch (36) and the hole (38) allow that the spring (32) is torsionally loaded so as to also maintain the upper body part (14) in its working position of Figure 2, even when the garden trim is not working.
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To mount the head (10), the body part upper (14) is mounted on the center piece (16) of the workpiece lower body (12) so that the radial teeth (24) of the upper body piece (14) completely enter the corresponding grooves (22) of the centerpiece (16). In this point, the coil spring (32) is inserted by inserting its end lower (34) in the notch (36) of the upper body part (14) and its upper end (35) in the hole (38) of the element ring (40), which is also mounted on the centerpiece (16) of so that its inner projections (44) are in the corresponding grooves (22). Before this last operation, the annular element (40) must be rotated in the direction of the arrow (M) of figure 1 in order to torsionally load the spring (32). By pushing down the annular element (40) against the spring (32), prevents it from being removed from the centerpiece (16) inserting the split retaining ring (42) into the groove ring discontinuous (46). At this point, by the action of the pier (32), the radial teeth (24) of the upper body part (14) they become located at the closed end of the part horizontal (26) of the L-shaped grooves (22) corresponding, then the head (10) being in its condition of work (figure 2).

It is evident that simply using a screwdriver, the split spring (42) can be removed and, by consequently, the annular element (40) to allow the two body parts (12) and (14) are separated, disassembling completely in this way the head (10). As you can see from figure 1, a protuberance (48) is arranged in an intermediate position along the vertical part of each of the four L-shaped grooves (22). The bumps (48) represent what has previously been called the means for  allow the upper body piece to also assume a second position, in which the cutting means can be replaced. With the head (10) mounted, the corresponding radial tooth (24) of the upper body piece (14) can rest on each one of said protuberances (48) to arrive at the situation of the Figure 3, in which the upper body part (14) is maintained separated from the lower body part (12), so that the eyelet (not shown) of pivoting cutter means to the head may be mounted on the corresponding fixed pivot (18) of the in the same way that the cutting means can be removed from the pivots (18) when they have to be replaced due to wear or be damaged In relation to this, the media can be used cutters (28) and (30) of Figure 4 (shown as two different types).

To reach the head arrangement (10) shown in figure 3 (in which the media can be replaced cutters) based on their working condition (figure 2), the upper body piece (14) must be held with one hand and must rotate around the lower body part (12) in the opposite direction to the arrow (M) in figure 1 to overcome the torque of forces exerted by the spring (32) (which is preloaded so torsional as indicated). The upper body part (14) it must then be pulled up against the coaxial force exerted again by the spring (32), so that the teeth Radials (24) of the upper body part (14) pass beyond of the level of the protuberance (48). If the body part is released superior (14) at this point, the torque and force of axial recovery exerted on the upper body part (14) by the spring (32) make the teeth (24) meet automatically on the corresponding bumps (48), to reach the condition shown in figure 3 in which They can replace the cutting means.

To return the head (10) to its condition of work of figure 2, the upper body piece (14) is made turn with one hand as much as possible in the direction of the arrow (R) of figure 4, and then released. By the action of spring (32), the upper body part (14) is hooked automatically down, but at the same time rotates in the opposite direction to the arrow (R), so that your teeth (24) are automatically placed at the closed end of the horizontal part (26) corresponding to the groove (22), to reach the condition of figure 2.

As already indicated, the media cutters of which the head (10) of figure 4 is provided are  of two different types, although both are equipped with an eyelet (no shown for simplicity) to swing the fixed pivots (18) respective. Specifically, this figure shows two means cutters (28) with disposed blades facing each other, and two means flexible linear double element cutters, also arranged faced, of the type already described. In relation to this, it has found that it is convenient for certain uses to use media Cutters of different type on the same head. Due to the speed and ease with which media can be replaced head cutters (10) without tools, it is tempting change them, as required, by appropriate cutting means to specific use (for example cutter media suitable for cut normal grass, or specifically for weeds resistant, or the type of grass that is close to obstacles). However, it is clear that the cutting means mounted on the head (10) can all be of the same type, for example all of blade type or all of the cited type comprising one or more flexible linear elements.

From the figures, you can also see that the upper body part (14) has means (50) for this purpose to facilitate its holding by hand to perform these operations which allow replacing the cutting means (28), (30), the means (50) consisting essentially of two projections facing on the edge of the upper body piece (14).

The lower body part (12), the piece of upper body (14) and the annular element (40) can be of aluminum or alloys thereof (especially if they are for professional garden trimmers), or of a plastic material suitable, for example the one that is already used to produce heads known.

Finally, it should be noted that with the head of the present invention, no tool is required  to replace the cutting means, the hands being sufficient, and that replacement is very fast and simple. In addition, it will be evident to a person skilled in the art, once the accompanying figures, that the head shown in them It has an undoubtedly small diametral dimension.

Claims (16)

1. Rotary head (10) for garden trimmers, of the type having its cutting means (28, 30) pivoting in the head (10), comprising a lower body part (12) and an upper annular body part ( 14), the lower body part (12) can be coaxially fixed to the drive shaft (20) of the trimmer and having several fixed pivots (18), parallel to the axis of rotation (20) of the head (10), to pivot the means cutters (28, 30) provided with an eyelet, the upper body part (14) being coaxially applied in its working position to the lower body part (12), position in which the cutting means (28, 30) are retained on the corresponding fixed pivots (18), characterized in that the fixed pivots (18) protrude upwards from the lower body part (12), and because to apply the upper body part (14) to the lower body part ( 12) in said working position, connection means are provided n of bayonet (22, 24) that require a coaxial movement to make the two body parts (12, 14) approach each other and a rotation of the upper body part (14) around the lower body part ( 12), this rotation being opposite to the direction of rotation (R) of the head (10) when it is working. 2. Head (10) according to claim 1, in which are provided elastic means (32) that oppose the removal of the upper body part (14) from its position of job. 3. Head (10) according to claim 1, in which means (48) that allow the upper body piece (14) also assume a second position, in which you can replace the cutting means (28, 30), are associated with bayonet connection means (22, 24). 4. Head (10) according to claim 3, in which are provided elastic means (32) that oppose the removal of the upper body part (14) from said position in the that the cutting means (28, 30) can be replaced. 5. Head (10) according to claim 1, in which the bayonet connection means comprise several angularly equidistant L-shaped grooves (22) arranged on the side surface of a centerpiece that protrudes upwards (16) with which the piece of lower body (12), and corresponding radial teeth (24) arranged inside the upper annular body part (14) to cooperate with the L-shaped grooves (22) of the piece lower body (12). 6. Head (10) according to claims 2, 4 and 5, in which the elastic means that oppose the withdrawal of the upper body part (14) of its working position and the elastic means that oppose the removal of the body part upper (14) of the position in which the cutter means (28, 30) consist of the same coil spring (32) that can receive torsion and compression load, mounted on the centerpiece (16) and acting directly or indirectly between the upper body part (14) and lower body part (12). 7. Head (10) according to claims 3 and 5, in which the means that allow the body piece upper also assume a position where they can be replaced the cutting means (28, 30) comprise protuberances (48) on which can rest the radial teeth (24) of the piece of upper body (14), each of these being arranged bumps (48) in an intermediate position along the vertical part of an L-shaped groove (22) correspondent. 8. Head (10) according to claim 5, in the one that the L-shaped grooves (22) and the bumps (48) of the lower body part (12) and the radial teeth (24) corresponding of the upper body piece (14) are a total of four. 9. Head (10) according to claim 1, in which the fixed pivots (18) of the lower body part (12) They are a total of four. 10. Head (10) according to claim 5, in which an annular element (40) can be mounted on a part default of the upper end of the centerpiece (16), means (42, 46) being provided to prevent withdrawal accidental element (40). 11. Head (10) according to claims 6 and 10, in which one end (35) of the coil spring (32) is attachable with the annular element (40) and the other end (34) of the spring (32) is attachable with the upper body part (14) for allow the spring (32) to be torsionally loaded, being provided means (44) to prevent rotation of the annular element (40) when the latter has been mounted on the centerpiece (16). 12. Head (10) according to claim 10, in which means to prevent accidental removal of the item annular (40) of the central part (16) comprise a ring of split retention (42) and a discontinuous annular groove (46) arranged next to the upper end of the centerpiece (16) to only partially receive the split retaining ring (42), preventing the latter from protruding (42) from the groove (46) the removal of the annular element (40).

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13. Head (10) according to claim 11, in which means to prevent rotation of the annular element (40) around the center piece (16) of the lower body part (12) comprise projections (44) arranged inside the annular element (40) to engage in the vertical part of a corresponding L-shaped groove (22). 14. Head (10) according to claim 1, in the one that the upper body piece (14) presents, so peripheral, means (50) to facilitate its holding by hand in order to carry out those operations that allow the cutting means (28, 30). 15. Head (10) according to claim 1, in whose body (12, 14, 10) is made of aluminum or alloy same. 16. Head (10) according to claim 1, in the one whose body (12, 14, 10) is made of plastic material.